Flexible tip for co n du cti n g - co r ds



(No Model.)

G. K. THOMPSON.

FLEXIBLE TIP FOR GONDUOTING OORDS. No. 317,887. Patented May 12, 1885.

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UNITED STATES PATENT Orrrcn.

GEORGE K. THOMPSON, OF MALEEN, ASSIGNOE TO THE AMERICAN BELL TELEPHONE COMPANY, OF BOSTON, MASSACHUSETTS.

FLEXIBLE TiP FOR CONDUCTlNG-CORDS.

SPECIFICATION forming part of Letters Patent No. 317,887, dated May 12, 1885,

(X model.)

To all whom, it may concern Be it known that I, GEORGE K. Tnonrson, residing at Malden, in the county of Middlesex and State of Massachusetts, have invented certain Improvements in Flexible Tips for Oonducting-Cords, of which the following is a specification.

My invention is an improvement in the flexible conducting-cord used on switch-boards,

IO telephonic, medical, and other similar electrical apparatus.

The object of the invention is to provide for the construction of a conducting-cord which shall be flexible from one terminal connection to the other, and thus avoid the liability to breakage at the point where the tip and conductor proper are joined, as is the case with cords now in use.

As at present constructed, flexible conduct- 2( ing-cords are formed of several strips of tinsel combined to form a single conductor of great flexibility. This is covered with a jacket of insulating material. A wire of considerable resilience, helically disposed upon a cord or string to give additional strength, is sometimes used as a substitute for the tinsel. The end of the conductor must be strengthened and protected by a tip, usually consisting of a cup or short tube of small diameter, into which the end of the flexible cord is secured, as by soldering. Upon the free end of this tubular section is a pin or needle of greater strength and cross-section than the strand of conductor forming the cord. This needle is for insertion 3 5 into the screw-cup provided for the purpose, fixed upon the switch or instrument, as is well understood. The difliculty with these cords arises from the liability of the conductor to break off short at the point of j unotion between 0 the cord and tubular section forming the tip, and is due, as I have found by practical use of such cords, to the inflexibility of the tip or terminal. IVhen an instrument to which one of these cords is attached is subjected to frequent movement, the bend comes most frequently at the junction between cord and tip. This soon makes the junction the weakest point in the cord, and if the portable instrument, as a telephone, be dropped, bringing up suddenly at the end of the cord, a break is almost inevitable. The same trouble occurs when the gravity take-up is applied to flexible cords, as is customary on switch-boards.

To remedy these defects my invention eonsists in a tip or terminal having flexibility and resiliency in all directions. I prefer to construct it of wire formed into a tube by a series of helical convolutions, suflicient in number to give the desired length of tube, one end beto ing cut off short at the end of a convolution and the opposite end extended in a line with the axis of the tube, to form the needle or tip for insertion into the screw-cup.

The accompanying drawing illustrates my invention applied to a double conducting-cord used in connection with the telephone. One branch of the cord is shown'bearing the flexible tip complete. The tip of the second branch is shown in longitudinal cross-section, and 7c slightly removed from the end of the flexible conductor.

T is the tip, preferably formed from spring brass wire, with a series of helically-disposed convolutions, the successive turns forming a tube of suflicient length and interior diameter to receive the terminal of the conductor '6, which is soldered into position or otherwise firmly fixed. One end of this wire is cut off close up to the end 0 ofa convolution. The op posite end is extended in a line with the axis of the tube, forming a needle, a, to be placed in a perforated screw-cup provided for the purpose.

A tip thus formed will be flexible and resili- 8 5 ent, yielding both to transverse and longitudinal strains. By the use of such a tip the difficulties above referred to will be obviated.

\Vhat I claim, and desire to secure by Letters Patent, is

1. A conducting cord having a flexible, yielding, and resilient tip constructed of wire formed into a tube or cylinder by successive helically-disposed convolutions.

2. A conducting -cord having a flexible, 5 yielding, and resilient tip constructed of wire formed into a tube or cylinder by successive helicallydisposed convolutions of substantially uniform diameter, terminating in a neescribing witnesses, this 26th day of January, die or point. 1885.

3. A flexible oonductin -oord having a tip constructed of spring brzf ss wire formed for GEORGE DHOMPSON' 5 a portion of its length into a spiral.

In testimony whereof I have signed my name to this speoifioation,in the presence of two sub- WVitnesses:

WM. B. VANSIZE, GEO. WILLIs PIERCE. 

